Xintiangou Formation

The Xintiangou Formation is a geological formation in China. Part of the stratigraphy of the Sichuan Basin, it is of an uncertain Middle Jurassic age, with preliminary U-Pb estimates giving an age range of 170 ma. It predominantly consists of interbedded mudstone and sandstone, with subordinate shelly limestone. At the Laojun site remains of lungfish, bony fish, freshwater sharks, temnospondyls, plesiosaurs,^[1][2] crocodyliformes, the Xinjiangchelyid turtle Protoxinjiangchelys and tritylodontids are known.^[3] The dinosaurs Sanxiasaurus, Yunyangosaurus, and indeterminate sauropods are also known from the formation.^[4][5] Theropod and ornithopod tracks have also been reported from the formation.^[6][7]

Xintiangou Formation
Stratigraphic range: Late Toarcian-Aalenian 180–170 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Type	Geological formation
Underlies	Shaximiao Formation
Overlies	Ziliujing Formation
Thickness	Over 400 metres (1,310 ft)
Lithology
Primary	Mudstone, Sandstone
Other	Limestone
Location
Region	Sichuan
Country	China
Extent	Sichuan Basin

References

1. Zhang, Feng; Yu, Hai-Dong; Xiong, Can; Wei, Zhao-Ying; Peng, Guang-Zhao; Wei, Xue-Fang (December 2020). "New freshwater plesiosaurian materials from the Middle Jurassic Xintiangou Formation of the Sichuan Basin, southwestern China". Journal of Palaeogeography. 9 (1): 23. doi:10.1186/s42501-020-00072-y. ISSN 2524-4507.
2. Ma, Qingyu; Li, Ning; Lin, Yu; Xiong, Can; Wei, Xuefang (2023-10-11). "Isolated freshwater pliosaurid teeth from the Middle Jurassic Xintiangou Formation of Chongqing, China". Historical Biology: 1–10. doi:10.1080/08912963.2023.2268617. ISSN 0891-2963. S2CID 264056915.
3. Hu, Xufeng; Li, Lu; Dai, Hui; Wang, Ping; Buffetaut, Eric; Wei, Guangbiao; Xiong, Can; Tong, Haiyan (August 2020). "Turtle remains from the Middle Jurassic Xintiangou Formation of Yunyang, Sichuan Basin, China". Annales de Paléontologie. 106 (4): 102440. doi:10.1016/j.annpal.2020.102440. S2CID 225451666.
4. Li, Ning; Dai, Hui; Tan, Chao; Hu, Xufeng; Wei, Zhaoying; Lin, Yu; Wei, Guangbiao; Li, Deliang; Meng, Li; Hao, Baoqiao; You, Hailu (2019-10-31). "A neornithischian dinosaur from the Middle Jurassic Xintiangou Formation of Yunyang, Chongqing, China: the earliest record in Asia". Historical Biology. 33 (7): 1089–1102. doi:10.1080/08912963.2019.1679129. ISSN 0891-2963. S2CID 209583081.
5. Hui Dai; Roger Benson; Xufeng Hu; Qingyu Ma; Chao Tan; Ning Li; Ming Xiao; Haiqian Hu; Yuxuan Zhou; Zhaoying Wei; Feng Zhang; Shan Jiang; Deliang Li; Guangzhao Peng; Yilun Yu; Xing Xu (2020). "A new possible megalosauroid theropod from the Middle Jurassic Xintiangou Formation of Chongqing, People's Republic of China and its implication for early tetanuran evolution". Scientific Reports. 10 (1): Article number 139. doi:10.1038/s41598-019-56959-x. PMC 6954265. PMID 31924836.
6. Xing, Lida; Peng, Guangzhao; Ye, Yong; Lockley, Martin G.; Klein, Hendrik; Persons, W. Scott; Zhang, Jianping; Shu, Chunkang; Hao, Baoqiao (2014-04-03). "Sauropod and Small Theropod Tracks from the Lower Jurassic Ziliujing Formation of Zigong City, Sichuan, China, with an Overview of Triassic–Jurassic Dinosaur Fossils and Footprints of the Sichuan Basin". Ichnos. 21 (2): 119–130. CiteSeerX 10.1.1.663.3037. doi:10.1080/10420940.2014.909352. ISSN 1042-0940. S2CID 129220218.
7. Xing, Lida; Lockley, Martin G.; Wang, Yongdong; Pole, Mike S.; Klein, Hendrik; Peng, Guangzhao; Xie, Xiaoping; Zhang, Guoquan; Deng, Chuntao; Burns, Michael E. (August 2017). "New Middle Jurassic dinosaur track record from northeastern Sichuan Province, China". Swiss Journal of Palaeontology. 136 (2): 359–364. doi:10.1007/s13358-016-0123-4. ISSN 1664-2376. S2CID 132256539.